Equipment and Infrastructure support for the PICO/PICASSO Dark Matter Search Project

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The quest for the mysterious missing mass of the Universe has become one of the big challenges for today's particle physics and cosmology. Astronomical observations show that only 1% of the matter of the Universe is luminous and there is now convincing evidence that 85% of all gravitationally traceable matter in the Universe is of a new exotic kind, different from the "ordinary" matter surrounding us with its protons, neutrons and electrons. This so-called Cold Dark Matter (CDM) is thought to consist of so-called WIMPs (Weakly Interacting Massive Particles), neutral particles, about ten to thousand times heavier than a proton and which interact extremely weakly with each other and ordinary matter. The PICASSO* dark matter experiment is tuned to the search for WIMPs. It is based on liquid-to-vapour phase transitions which can be induced by WIMP interactions with nuclei in metastable superheated droplets. The powerful background discrimination features of the superheated liquid technique discovered by PICASSO promise “background blind” operation for up to tonne - year exposures. Therefore in December 2012 the two leading groups in the field of dark matter searches with superheated liquids, PICASSO and COUPP joint forces within the new PICO collaboration to work together towards a 500 kg dark matter experiment at SNOLAB. With superheated C4F10 or C3F8 as the active target in a 250L bubble chamber this experiment meets the definition of a next generation dark matter experiment (G2) and no other G2 experiment would have comparable sensitivities in the sectors of spin-dependent interactions and light WIMP masses. The Canadian PICASSO / PICO contingent consists of research groups of five institutions: University of Alberta, Laurentian University, Université de Montréal, Queen’s University and University of Toronto. In this grant request we ask for infrastructure and equipment support for the completion of a serious of R&D projects which are part of the preparatory phase of the 500 kg detector. *Project In Canada to Search for Supersymmetric Objects Projet d'Identification de CAnditats Supersymetriques Sombres